[Double isotope albumin flux measurement: diagnosis and therapeutic monitoring of acute lung injury].

PURPOSE

Acute Lung Injury (ALI) is a clinical condition which is associated with a high lethality. It is characterized by an increased pulmonary capillary permeability and non-cardiogenic pulmonary edema. This study was designed to answer the question whether double isotope albumin-flux measurement is a useful tool both for diagnosis of increased pulmonary capillary permeability and for monitoring therapeutic interventions (nitric oxide (NO) inhalation).

METHOD

In 12 patients with clinical signs of ALI, transvascular albumin-flux was measured by a double radioisotope technique before, during and after NO inhalation. 99mTc labeled albumin and 51Cr labeled autologous erythrocytes were used as tracer. The radioactivity of both radiopharmaceuticals was measured externally over the right lung by a radiation probe and simultaneously in arterial blood. For quantification of transvascular albumin-flux Normalized Index (NI) and Normalized Slope Index (NSI) were calculated. Furthermore, pulmonal vascular pressures and other physiological parameters were recorded.

RESULTS

All 12 patients showed markedly increased NSI before inhalation of NO. NSI decreased from 0.0074 +/- 0.0046 min-1 without nitric oxide to -0.0051 +/- 0.0041 min-1 during nitric oxide and increased to 0.0046 +/- 0.0111 min-1 after nitric oxide. The decrease of the NSI correlated well with decrease of venous pulmonary resistance during inhalation of NO.

CONCLUSION

Inhalation of NO reduces transvascular albumin-flux in patients with ALI. Double isotope albumin-flux measurement enables diagnosis of increased capillary permeability as well as monitoring therapeutic interventions.